1. Field of the Invention
The present invention relates to an apparatus for an internal combustion engine mounted on an automobile or the like, and particularly to a high pressure fuel supply apparatus including a high pressure fuel pump.
2. Description of the Related Art
Present automobiles are required to reduce emission gas substances such as carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx), which are included in emission gas of the automobiles, from the viewpoint of environmental conservation, and for the purpose of reduction of the emission gas substances, development of a direct injection engine has been carried out. In the above described direct injection engine, a fuel within a common rail of which pressure is regulated into a high fuel pressure by a high pressure fuel pump is directly injected into a combustion chamber of a cylinder by an injector, to attempt reduction or the like of the emission gas substances due to engine output improvement and combustion improvement.
The regulation of the fuel pressure in the above described common rail is performed by regulating a fuel discharge quantity from the above described high pressure pump connected to a camshaft for intake or exhaust of the internal combustion engine. In the conventional art, the fuel discharge quantity from the high pressure fuel pump is operated in synchronization with the above described camshaft, and therefore regulated by performing desired fuel discharge quantity control by changing the timing of ON and OFF of the solenoid valve in a high pressure pump in accordance with the phase of the camshaft.
As such an art, there is known the one described in JP-A-2005-76554, for example. It is known, as a control method of the fuel discharge quantity of the high pressure fuel pump having a variable valve timing system, that the apparatus of this publication controls the ON/OFF timing of the solenoid valve from a camshaft sensor by using a camshaft sensor signal which synchronizes with the rotation of the camshaft with the camshaft sensor signal as an origin, for the purpose of simplification and enhancement of control precision of the ON/OFF control timing of the solenoid valve in the high pressure fuel pump for controlling the discharge position of the high pressure fuel pump with respect to the control position of the variable valve timing. This publication shows a method of coping with both calculation load of a CPU in the control system and control precision of the high pressure pump compatible, which method does not require performing complicated correction of the ON/OFF timing of the above described solenoid valve with respect to the control position of the variable valve timing by using the camshaft sensor signal as an origin, and further, properly uses a method of ensuring angle control precision by the crankshaft sensor signal in addition to the camshaft sensor signal information in accordance with the operating state of the internal combustion engine, and a method of controlling the ON/OFF timing of the above described solenoid value only by the above described camshaft sensor signal information without using the crankshaft sensor.